1. Field of The Invention
The invention relates to a multi-functional mould convertable from transfer mould to injection mould, particularly for encapsulating chips placed on lead frames, comprising mutually movable mould halves on the mutually facing surfaces of which cavities are arranged for receiving chips for encapsulating, means for ejecting finished product out of the mould, runners for the passage of encapsulating material to the cavities and a feed opening in one of the mould halves for admitting encapsulating material.
2. Description of the Prior Art
Such a mould is known from Modern Plastics, vol. 47, no. 07, Jul. 1970, Lausanne CH, pages 102-104; R. Paci "Now it's easy to convert from transfer to injection moulding".
Chips arranged on lead frames are normally encapsulated with material by means of the so-called transfer method. An example of such a method and device suitable therefor is described inter alia in the European patent application No. 89.203003.2. With this known method and device a pellet-like piece of encapsulating material is placed in a space suitable for this purpose, pressure is applied on the pellet by means of a plunger and a temperature increase effected such that it becomes liquid and moves through runners suitable therefor to the mould cavities. Materials with a thermosetting character are used as encapsulating material.
In addition to the transfer method, encapsulating material can also be processed as is usual in injection moulding devices. Materials used herein have a thermoplastic character.
The known mould should be machined for conversion of the mould in order to have the means extended. This makes it extremely difficult and cumbersome to reconnect the mould again.